A class has 20 boys with average score 60 and 30 girls with average score 70. What is the class average?
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The total score is 20 × 60 + 30 × 70 = 3,300.
Dividing by 50 students gives 66.
Practice Pakistan questions with answers and explanations.
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The total score is 20 × 60 + 30 × 70 = 3,300.
Dividing by 50 students gives 66.
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The total ratio parts are 7, so one part is 35/7 = 5 liters.
Water is two parts, or 10 liters.
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Thirty percent of 20 liters is 0.30 × 20.
This equals 6 liters.
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The solution contains 4 liters of salt, which remains unchanged.
For salt to be 25%, total volume must be 16 liters, so 6 liters are added.
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For direct variation, x/y is constant.
The constant is 18/6 = 3, so x = 3 × 10 = 30.
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The greatest common divisor of 24 and 36 is 12.
Dividing both terms by 12 gives 2:3.
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Three ratio parts correspond to 24, so one part is 8.
Girls represent five parts, giving 5 × 8 = 40.
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The total number of ratio parts is 9, so one part is 720/9 = 80.
The largest share is 4 × 80 = Rs. 320.
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Make the common term b equal in both ratios.
Multiplying 4:7 by 2 gives 8:14, so a:b:c = 8:14:15.
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The cost per pen is 150 ÷ 5 = Rs. 30.
Eight pens cost 8 × 30 = Rs. 240.
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Workers and time are inversely proportional for fixed work.
Thus, 12 × 15 = 20 × days, giving 9 days.
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The sum is 12 + 18 + 20 + 30 = 80.
Dividing by 4 gives an average of 20.